1. Field of the Invention
The present invention relates to hearing aids. The invention, more specifically, relates to a hearing aid having means for alleviating tinnitus. The invention further relates to a method for adjusting a hearing aid.
2. The Prior Art
A device for treating tinnitus is known from WO-A2-2008/087157. The device comprises a generator means for generating an audio signal and a transducer means for reproducing the audio signal having interposed between them a filter. The filter is matched to suppress the audio signal in an interval of frequencies around a dominant frequency of a tinnitus. WO-A2-2008/087157 also describes a method for matching the filter to enable the suppression by estimating the subjective intensity and the dominant frequency of tinnitus. The subjective intensity is estimated by means of an audiometric procedure, while the dominant frequency is estimated by means of the signal generator of the device.
This method implies that the frequencies used to estimate the subjective intensity and the frequencies identified by the estimation of the dominant frequency may differ from each other. This may result in that the peak frequency in the frequency spectrum of the estimated subjective intensity and the estimated dominant frequency differ from each other. This in turn has the implication that the matching of the filter is affected such that either an inconveniently large spectral width of the filter will be necessary or the tinnitus may not be sufficiently suppressed.
Furthermore, the known matching method is, due to its use of audiometric measurements and following dependence on extensive and complicated equipment, confined to be performed by qualified staff, thus rendering exploitation of the advantages related to the use of the matching procedure outside the laboratory rather cumbersome.
In a related method for alleviating tinnitus, a patient listens, on a regular basis, to music where the music is modified to contain no energy in the frequency range surrounding the, individually determined, tinnitus frequency of the patient. According to this method the patient chooses music that he or she finds enjoyable, and receives a recording of the music, which has been modified as described above. See “Listening to tailor-made notched music reduces tinnitus loudness and tinnitus-related auditory cortex activity”, Proceedings of the National Academy of Sciences of the United States of America, Jan. 19, 2010 vol. 107 no. 3, pp. 1207-1210.
This method of tinnitus alleviation is inflexible insofar as the patient, as part of the alleviation, can only listen to the music that has been modified and stored on some audio media. This may especially be problematic since the method is a long term alleviation, which is partly based on the requirement that the patient finds the music enjoyable. Another problem arises if the audio media is lost, damaged or for some reason not brought along by the patient.